Phenomenological Mean-Field Theory of Metamagnetism in Heavy Fermion Compounds under Constant Pressure Conditions with Application to CeRu2Si2

Abstract

To understand metamagnetism in specific heavy fermion compounds, we explored the phenomenological mean-field theory with magnetic interaction by using the heavy fermion characteristic temperature Tm without a microscopic mechanism. We describe an extension of the Landau-like free energy density with Bragg–Williams entropy. By minimizing this free energy density with respect to the magnetization, we obtained thermal equilibrium quantities in theoretical terms. For the heavy fermion system with the large Grüneisen parameter, we used the scaling hypothesis to take account of the volume dependence in the experimental data under constant pressure conditions. As an example, the magnetic behaviors of the CeRu2Si2 with a paramagnetic ground state is examined and explained in qualitative terms.